Front element of lens stuck in shutter.

[Krist]

Hi,
Im still quite new to large format. I recently got a Sinaron 75mm f4.5 lens and wanted to remove the front element to clean the glass. It is completely stuck in the shutter, the back element comes of quite easy. Am i doing somthing wrong here just trying to turn it?
Is it even an issue if i cant get it off as long as the shutter works?

Kristian

 

[shutterfinger]

Sometimes one has to grip the element with a rubber jar opener or a rubber strap wrench and apply a lot of pressure to break the lens cell loose without deforming the lens barrel or bending the filter threads.

 

[Don_ih]

Take the shutter out of the board - it'll give you a better grip.

 

[BrianShaw]

 

[voceumana]

Sometimes even just wrapping the outside of the lens barrel with masking tape will let you get a good grip on it.

 

[mshchem]

Yikes go slow. A drop of solvent maybe. The old American shutters that are aluminum are horrible.

 

[mshchem]

Hi,
Im still quite new to large format. I recently got a Sinaron 75mm f4.5 lens and wanted to remove the front element to clean the glass. It is completely stuck in the shutter, the back element comes of quite easy. Am i doing somthing wrong here just trying to turn it?
Is it even an issue if i cant get it off as long as the shutter works?

Kristian

View attachment 273060

I would go ahead and use it. One option would be to open the aperture ALL the way, lock open the shutter in T mode and use a small cotton swab and your breath on the back of the front lens group. You touch anything but the glass and you could ruin the shutter.

 

[mshchem]

View attachment 273068

No. These things are great but can apply immense amounts of force. Of course in the hands of a skilled individual

 

[Krist]

I would go ahead and use it. One option would be to open the aperture ALL the way, lock open the shutter in T mode and use a small cotton swab and your breath on the back of the front lens group. You touch anything but the glass and you could ruin the shutter.

I did just that and i guess it solved the "issue". I just thought it could mean something was wrong in some way with the shutter or the glass.

 

[Krist]

Take the shutter out of the board - it'll give you a better grip.

I did and it is impossible to move, plus I honestly dont think there is a good way to "grab" the shutter without potential break something on it..

 

[Krist]

W

Yikes go slow. A drop of solvent maybe. The old American shutters that are aluminum are horrible.

here would you drop that? and what to use?

 

[mshchem]

W

here would you drop that? and what to use?

Well, it may be of little value. I've used old Kodak movie film cleaner. Solvents are a mixture of heptane and CFC-113. The CFC-113 was a great Solvents, banned for obvious reasons. I'm not sure where you are located. In the US people have used "lighter fluid" i.e. "Ronsinol" this is just a blend of naphtha.
Personally I would be extremely careful. If you get anything on the shutter blades you may mess up the speeds and need the help of a professional.
I would use a needle to apply a single drop or two, and then wait.
It's probably just frozen, and brute force may just destroy the shutter.

 

[Keith Pitman]

Put it in the freezer for an hour,then use a strap wrench on the front element. Avoid “solvents.”

 

[reddesert]

Once you've cleaned the rear surface, there is no real reason to take the front cell out of the shutter. If you had to get some solvent in there, the place to put it would be where the front cell meets the shutter, so that the solvent or lubricant wicks into the threads, and no more than a drop. You don't want it to get into the workings of the shutter. I would *not* use a strap wrench on it unless there was something really wrong that I needed to fix. A rubber band around the front cell and gripping it with your hand is usually enough. But in this case, it's probably best to just use the lens and not mess with it.

 

[removed account4]

Put it in the freezer for an hour,then use a strap wrench on the front element. Avoid “solvents.”

+1

years ago showed me how rubber bicycle tire works great as a "grip"
inexpensive and useful like w windshield wiper for a squeegee

 

[Krist]

Put it in the freezer for an hour,then use a strap wrench on the front element. Avoid “solvents.”

What is the point about the freezer, to make the metal retract or?
I might wanna try that but could the cold not make the oil in the shutter bad?

 

[Krist]

Once you've cleaned the rear surface, there is no real reason to take the front cell out of the shutter. If you had to get some solvent in there, the place to put it would be where the front cell meets the shutter, so that the solvent or lubricant wicks into the threads, and no more than a drop. You don't want it to get into the workings of the shutter. I would *not* use a strap wrench on it unless there was something really wrong that I needed to fix. A rubber band around the front cell and gripping it with your hand is usually enough. But in this case, it's probably best to just use the lens and not mess with it.

Okay, a rubber band seems more reasonable.
Thank you

 

[shutterfinger]

What is the point about the freezer, to make the metal retract or?

Metal contracts when cold, expands when hot. Seal in a plastic bag before putting it in the freezer.

might wanna try that but could the cold not make the oil in the shutter bad?

Most oils and grease are good to 0°F, the freezer is 20°F to 30°F.

I prefer to heat the oven to 300°F, turn it off, place the piece on the center rack, close the door and leave for 30 minutes. Works well and does no harm.

 

[Rick A]

View attachment 273068

NO. These create non uniform pressure points and can deform a lens. Ask me how I know.

 

[shutterfinger]

NO. These create non uniform pressure points and can deform a lens. Ask me how I know.

Only when not used correctly.

 

[BrianShaw]

“the freezer is 20°F to 30°F.”
The most commonly recommended freezer temp is 0 degrees F.

 

[BrianShaw]

NO. These create non uniform pressure points and can deform a lens. Ask me how I know.

They must be used carefully and gently. If you treat the lens like a plumbing fixture then, sure, damage may result. I’d try a rubber grip first and if that didn’t work...

Ask me how I know.

 

[grat]

Typically, cold may cause an oil to congeal and become more viscous-- but it won't cause deterioration, unlike heat. So if you do chill your shutter in the hope that different expansion/contraction rates will free it up, don't operate the shutter while it's cold, let it thaw back to room temperature.

Personally, I would not use a strap-wrench-- if the lens is seriously stuck-in, I'd be concerned about the attachment point forming a lever arm, and placing too much stress on the lens housing.

Now, if you've got a rubber / silicone jar opener, on the other hand, that you can't put too much torque on...

 

[shutterfinger]

It takes some fineness to get the wrench set so that when pressure is applied to the handle the force applied remains 90° to the part to be turned. Rubber and nylon straps stretch as pressure is applied.

 

[Rod Klukas]

Hi,
Im still quite new to large format. I recently got a Sinaron 75mm f4.5 lens and wanted to remove the front element to clean the glass. It is completely stuck in the shutter, the back element comes of quite easy. Am i doing somthing wrong here just trying to turn it?
Is it even an issue if i cant get it off as long as the shutter works?

Kristian

View attachment 273060

Because the inside tube is brass or bronze and the lens barrels is Aluminum, the cold technique is a good try. However, as you can clean the rear surface of the front group from the rear, why worry and take a chance on messing up the shutter, anyway.
I would leave it alone. One can without much trouble, over torque a shutter and decenter a lens group. This would then result in you looking for a replacement shutter. Leave it alone. I have lenses, one of which I have used for over 30 years, and it is still fine despite the front group very tight.

The lens is a great one built by Rodenstock. It may also have some shims under the front barrel which you must be very careful not to lose either.

Anyway, some info to digest.